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U.S. Forces Are Leaving a Toxic Environmental Legacy in Afghanistan

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As U.S. forces withdrew from Afghanistan, the Taliban immediately rushed in, and it recently took over the country’s major cities in just a few days. The end of the two-decade American occupation has not only produced a fraught political situation; it has also created an environmental one. Some of the military bases the U.S. handed over to the Afghan national security forces—which this month stood down rather than continuing to contest a seemingly inevitable Taliban victory—hold toxic detritus that may never get a full cleanup.

The U.S. has operated some of these facilities for almost 20 years. As part of the sites’ routine functioning, the American military and its allied partners generated waste, including substances that increase the risk of cancer and other diseases. These materials can produce long-lasting environmental hazards in and around such sites as they seep into the ground, remain exposed in uncovered landfills and—when some items are incinerated—drift into the air as smoke particles.

A defunct military base may produce less pollution than an active one—for example, the uncovered remains of a burn pit present less direct harm than the active release of toxins from burning waste. But such a base still requires some degree of environmental remediation before it can be safely converted to civilian use. In a 2017 report, the Government Accountability Office estimated the final cost of such cleanups in bases closed inside the U.S. between 1988 and 2015 would be nearly $15 billion.

These sites can leave a substantial mark on their surroundings. For example, open-air burn pits are often used to dispose of waste in the field. They are common across areas where the U.S. has fought, despite the fact that an official Department of Defense policy prohibits them “except in circumstances in which no alternative disposal method is feasible.” This is because burning military material—everything from food waste to paint, metal, plastics, medical and human waste, and sometimes unexploded ordnance—can produce toxic smoke contaminated with “particulate matter, lead, mercury, dioxins, and irritant gases,” as outlined in a 2014 report by the Special Inspector General for Afghanistan Reconstruction (SIGAR). Inhaling these contaminants, the report continues, “can negatively affect organs and body systems, such as the adrenal glands, lungs, liver, and stomach,” causing conditions that include asthma, rhinitis and sinusitis. Although the Department of Veterans Affairs has anticipated and tracked related medical conditions among overseas deployments since 2001, the health impacts are hardly limited to uniformed personnel. As the American Public Health Association noted in a statement in 2015, “Afghan citizens face equal, if not greater, risk from exposure to burn pit pollutants. Nationals of the countries where these conflicts have taken place cannot leave as easily as occupying soldiers and must cope with the environmental aftereffects of war.”

Burn pits are primarily a source of harm while actively used to incinerate waste. But long-running or poorly tended burn pits within the U.S. itself have at times been so contaminated that they have been designated Superfund sites even after they were shut down. Contaminants from burn pits can include “polycyclic aromatic hydrocarbons, metals such as lead and copper, or other compounds in soil and potentially in sediment if a surface water body is in the vicinity,” says an official at the New York State Department of Environmental Conservation (NYSDEC). Cleaning up burn pits takes time and is hard enough to do domestically—let alone in a country now controlled by a hostile force.

Understanding the challenge of remediation outside of an active war zone can illustrate the baseline difficulties. For example, one nonmilitary cleanup in New York State focused on a burn pit used by an industrial manufacturer. The process required participants to monitor groundwater for contaminants and build up two feet of soil to enable passive decontamination by beneficial plants. “Long-term, direct contact to humans can be prevented or mitigated by placement of a clean soil cover over the area,” the NYSDEC official explains. But the remediation does not end with soil cover: for this particular burn pit, progress will need to be assessed again next year, about a decade after the effort. Like the site in New York State, long-running burn pits in Afghanistan destroyed solvents (among a variety of other waste), which means they could face similar cleanup problems.

Perfluoroalkyl and polyfluoroalkyl substances, commonly called PFAS, create another durable environmental hazard if they leach into the environment at military posts. These chemicals, which have uses ranging from nonstick pans to food wrappers, are also found in a specialized firefighting foam that many domestic and overseas U.S. bases use to put out petroleum fires. Exposure to PFAS has been linked to symptoms such as increased cholesterol levels, decreased infant birth weight, and a heightened risk of kidney or testicular cancer, among others.

Even within the U.S., cleaning up PFAS at military bases is a difficult process. One factor is that the Department of Defense is still just getting started on actual remediation. A June 2021 report by the Government Accountability Office found that the DOD “is early in the environmental restoration process at or near the 687 [domestic military] installations with a known or suspected release of” PFAS contained in firefighting foams.

In the past few decades, better practices for reducing contamination have somewhat mitigated the situation at U.S. bases. “The environmental remediation and compliance programs at DOD are fairly mature. They really came into their own in the 1990s and then grew from there,” says John Conger, former U.S. acting assistant secretary of defense for energy, installations and environment. “As DOD has been more diligent in compliance programs, the amount of pollution that it inserts into the environment decreases.” Despite this progress, some adaptations—such as the prohibition on burn pits—have only been adopted slowly and have not always been adhered to.

Cleaning up after military bases becomes vastly more difficult outside U.S. states and territories because of legal obstacles and the need for diplomacy with a foreign government. For these locales, the U.S. can fund the remediation of environmental hazards at its bases only while they are in use: when the military withdraws from a base, a specific rule prohibits the DOD from directly spending money or using its resources “to meet requirements that are the responsibility of host nations, as stipulated in applicable international agreements.”

“There is a legal prohibition that exists,” Conger says. “It prohibited the DOD from spending money for environmental remediation in other countries. So it’s against the law for [the DOD] to spend money there on cleanup.” A version of this rule was adopted in 1995 as part of the post–cold war realignment of U.S. forces across the globe. It specified that the U.S. could fund environmental remediation at a base in a host country—but that unless it was obliged by a binding international agreement or already approved cleanup plan, the DOD would be prohibited from doing so for a base it no longer occupied. The department can share information about such hazards with the host country to assist in cleanup efforts, however. Just a few years later, the Institute for Policy Studies asserted that the “DOD has exploited this lack of explicit obligation by conducting the absolute minimum of environmental restoration at overseas bases.” The Office of the Assistant Secretary of Defense for Sustainment did not respond to a request for comment.

Because of the legal and practical obstacles, it was unclear what environmental remediation efforts would occur at former U.S. military bases in Afghanistan—even before the Taliban took over the country. Inquiries to Afghanistan’s National Environmental Protection Agency about what cleanup projects happened or were planned at U.S. military bases in Afghanistan were not answered before the change of government. SIGAR declined to comment, instead pointing to published reports. And at press time, the Assistant Secretary of Defense for Energy, Installations, and Environment has not responded to a request for comment. The United Nations Environment Program’s Afghanistan program has been unable to weigh in on hazards at military bases because it is helping ensure employee safety during the Taliban takeover.

“What happens when environmental damage occurs and a host nation or local national does not have the leverage or resources to demand compensation or demand mitigation from the U.S. military?” wrote Jennifer Neuhauser, then a judge advocate at the U.S. Army, in a 2015 paper. With a hostile power now in possession of these sites, the U.S. is unlikely to participate in local cleanup efforts. As Neuhauser stated in her paper, “There are very few enforcement mechanisms under international law to compel U.S. forces to resolve these issues.”

Born on the Radio | by Brian Koberlein

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Blog

15 August 2021

This artist’s impression shows a possible seed for the formation of a supermassive black hole.
NASA/CXC/M. Weiss
This artist’s impression shows a possible seed for the formation of a supermassive black hole.

The universe is littered with supermassive black holes. There’s one a mere 30,000 light-years away in the center of the Milky Way. Most galaxies have one, and some of them are more massive than a billion stars. We know that many supermassive black holes formed early in the universe. For example, the quasar TON 618 is powered by a 66 billion solar mass black hole. Since its light travels nearly 11 billion years to reach us, TON 618 was already huge when the universe was just a few billion years old. So how did these black holes grow so massive so quickly?

One idea is that some of the very first stars were giants. With a mass of more than 10,000 Suns, such a star would be very short-lived, and would quickly collapse into a large black hole. These first black holes would act as seeds in the center of a galaxy, consuming nearby material to grow quickly in size. Some of them would even collide and merge to form an even larger black hole. While it’s a reasonable model, computer simulations find that this process takes too long. This process can’t produce the kind of black holes we see in the early universe such as TON 618.

A direct image of the supermassive black hole in M87.
EHT Collaboration
A direct image of the supermassive black hole in M87.

Another idea is known as the direct collapse scenario. In this model, a small supermassive black hole forms all at once. Dense gas in the middle of a proto-galaxy cools enough to collapse under its own weight, forming a black hole. Since these black holes would have a head start on mass, they can quickly grow into the supermassive black holes we observe.

So far we haven’t been able to observe a direct collapse black hole (DCBH). A few years ago a couple of candidate DCBHs were discovered by their infrared signals. These might be confirmed when the James Webb Space Telescopes is (possibly) launched later this year. But recently a study argues that we might observe DCBHs by their radio signatures.

When black holes actively consume nearby matter, they can create powerful jets of hot plasma. These jets are radio loud and are one of the ways we identify supermassive black holes. Direct collapse black holes should have similar jets, but the jet material would be denser. And since DCBHs would form in the early universe, their radio signals would be more redshifted. This latest work argues that the radio signature of DCBHs would be similar in structure, but easily distinguishable from the radio jets we see today. The signature would also differ from jets created by seed black holes.

Unfortunately, these high-redshift radio sources can’t be seen by current radio telescopes. But they should be bright enough to be detected by the Square Kilometer Array (SKA) and the proposed next generation Very Large Array (ngVLA).

Roberto Maiolino awarded a Royal Society research professorship

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Prof Roberto Maiolino awarded a prestigious Royal Society Research Professorship!

From the Royal Society website:

“Professor Roberto Maiolino, University of Cambridge – The chemical evolution of galaxies across the cosmic epochs

Professor Roberto Maiolino is Professor of Experimental Astrophysics and Director of the Kavli Institute for Cosmology, Cambridge. Professor Roberto Maiolino seeks to underpin the chemical enrichment of distant galaxies, of which very little is known.

Professor Roberto Maiolino will use two new cutting- edge facilities to measure the chemical enrichment of galaxies out to the earliest epochs of galaxy formation with unprecedented accuracy and datasets of distant galaxies. This will enable him to discriminate between different scenarios of galaxy formation and ultimately trace chemical enrichment all the way back to the very first galaxies.”

More info:

https://www.phy.cam.ac.uk/news/professor-roberto-maiolino-awarded-a-royal-society-research-professorship

https://royalsociety.org/news/2021/01/royal-society-announces-research-professorships-2021/

Astrophiz 131: Dr Ian Musgrave’s August SkyGuide – Astrophiz: An Astronomy Podcast

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August Skyguide with Dr Ian ‘Astroblog’ Musgrave

Listen: https://soundcloud.com/astrophiz/astrophiz131-augustskyguide

In Eastern evening skies, magnificent Saturn and Jupiter loom large in opposition.Over in the West, Venus has a nice encounter with a fine crescent moon on the 11th.Also in the west, brilliant but half-phased Venus dominates our evening skies for everyone, and if you have a low western horizon you’ll see Mercury catching up with Mars on the 19th and counterintuitively is actually brighter than Mars for a while.The centre of our Milky Way galaxy is directly overhead (and Ian has tips for avoiding getting a crick in your neck 😉
For early risers, Saturn and Jupiter are also looking fine over in the West.
In Ian’s Tangent, we hear how planets, and even the moon, have have been mistaken for other objects and recommends safe evening walks to re-familiarise ourselves with all the celestial wonders that gaze down on us with their awe-inspiring indifference.
Ian’s ‘Astroblogger’ website and ‘Southern Skywatch’ both come up as the first result in all search engines.

Astrophotography from Sydney | Dr Ángel R. López-Sánchez

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Article originally written for the AAO’s Newsletter published on 29th June 2021.

During the last year I’ve been setting up my telescope in the backyard to do astrophotography as an amateur astronomer. This has been possible thanks to getting a good mount (Skywatcher AZ-EQ6-Pro) that allows me to do auto-guiding, and using a little but very clever device (it’s a modified Raspberri Pi manufactured by ZWO called “ASIAir”) that allows me to connect mount and cameras (the main camera for astrophotography and the auxiliary camera for auto-guiding) together, being everything controlled using my son’s iPad (who, with only 8 years, has been also helping me with all of this). In the last months I’ve been able to get a process so smooth that I only need 10 minutes for setup (checking polar alignment, guiding, focus) and then the telescope is observing all the night (it will automatically move to a parked position at the end of the run).

My amateur telescope equipment in April 2021
My amateur telescope equipment in the backyard (15 km from Sydney’s centre) ready for astrophotography in April 2021. The telescope is my Skywatcher Black Diamond 80, f=600mm (f/7.5) that I bought for the Transit of Venus 2012. The x0.8 Orion focal reducer is included here. I use the ZWO ASIAir to control the main camera, the mount (Skywatcher AZ-EQ6 Pro) and the guiding system (ASI120MM + Orion 50mm finderscope). The ZWO Filter Wheel has 7 positions with 2” filters (ZWO LBGR filters, Baader 3.5nn H-alpha, Antlia 3nm [O III], and a hand-made dark filter). The main camera is a ZWO 1600MM-Pro, usually set at -20C.

I must confess this has been a lot of fun for me, also for keeping extra busy and awake during the many meetings / workshops in the middle of the night we all are having lately. I’m getting some nice photos, particularly of nebulae, as I’m using some ultra-narrow (3.5nm thickness) H-alpha and [O III] filters. One of my favourite images is the Cat’s Paw nebula, who would have told me just some few years ago I will be able to get such an image with all these details using a 80mm refractor telescope in Sydney!

Fire in the Cat's Paw Nebula
Deep H-alpha image of the Cat’s Paw Nebula (NGC 6334) in Scorpius obtained from my backyard, 15 km from Sydney’s city centre. All the information in my Flickr. Credit: Ángel R. López-Sánchez (AAO-MQ).

Hence, when last May, I was starting to use TAIPAN and observing with this new instrument, I couldn’t help myself…

While Tayyaba and Anthony helped me to get trained for TAIPAN observing, I decided to check if the instrument could be used for observing HII regions in the outskirts of the nearby spiral galaxy M 83, as well as observing the dwarf galaxies in the neighbourhood. Unfortunately this has been hard for the 1.2m UKST because of the faintness of the targets, but at least I got some test data from the central parts of M83 and some dwarf galaxies, including beautiful starburst NGC 5253. 

However, I was thrilled to be using TAIPAN to observe M83 while, at the same time, in my backyard, my small telescope was also observing M 83 to get a new color-image of this galaxy. It was quite exciting and rewarding!

Colour image of M83  and surroundings combining data in B, G, R and Luminosity filters (8 hours in total combining 2 minute exposures). Data taken on 16 and 17 May 2021 while observing with TAIPAN remotely from my home office. This is still work in progress. Credit: Ángel R. López-Sánchez (AAO-MQ).

This image is still work in process, because we need to take usually hundreds of frames in each filter to get a good astronomical image to mitigate the light pollution plus reducing the background noise as much as we can. And, of course, dealing later with the processing of the data (it’s not that hard as it sounds, there is actually some software already available for amateur astronomers that does this very quickly in a very efficient way, even considering darks, flats, offsets and median stacking with different options). Also, I still need to add the H-alpha data in this image to emphasise the star-forming regions in the spiral disk of M 83. Unfortunately, the weather over Sydney during the last weeks has not being very good for astrophotography, but I hope to get the rest of the data soon.

Additionally, on Wednesday 26th May we enjoyed a total lunar eclipse. I took almost 2000 images of the event while I was participating in an online live event with many schools in Spain (8000+ views during the day). The telescope setup in this case was different, as I used my CANON 5D Mark III DSLR as main camera attached to my telescope. But, even though the totality of this lunar eclipse was short (only around 15 minutes), I got a very nice image of the eclipsed moon. For this image I combined the same data independently for getting the stars and the moon, and merged them together later.

Total Lunar Eclipse - 26 May 2021
Total Lunar Eclipse on 26th May 2021. This image combines 50 x 1″ exposures, ISO 800, obtained with my CANON 5D Mark III attached at primary focus of my Skywatcher Black Diamond 80mm f600mm (F/7.5) during the Total Lunar Eclipse on Wednesday 26 May 2021, between 9:00pm and 9:04pm, Sydney local time. Full description and high resolution image here. Credit: Ángel R. López-Sánchez (AAO-MQ).

Why is this weird, metallic star hurtling out of the Milky Way? Astronomers analyzed light data from a piece of supernova shrapnel to gain clues about where it came from — ScienceDaily

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About 2,000 light-years away from Earth, there is a star catapulting toward the edge of the Milky Way. This particular star, known as LP 40?365, is one of a unique breed of fast-moving stars — remnant pieces of massive white dwarf stars — that have survived in chunks after a gigantic stellar explosion.

“This star is moving so fast that it’s almost certainly leaving the galaxy…[it’s] moving almost two million miles an hour,” says JJ Hermes, Boston University College of Arts & Sciences assistant professor of astronomy. But why is this flying object speeding out of the Milky Way? Because it’s a piece of shrapnel from a past explosion — a cosmic event known as a supernova — that’s still being propelled forward.

“To have gone through partial detonation and still survive is very cool and unique, and it’s only in the last few years that we’ve started to think this kind of star could exist,” says Odelia Putterman, a former BU student who has worked in Hermes’ lab.

In a new paper published in The Astrophysical Journal Letters, Hermes and Putterman uncover new observations about this leftover “star shrapnel” that gives insight to other stars with similar catastrophic pasts.

Putterman and Hermes analyzed data from NASA’s Hubble Space Telescope and Transiting Exoplanet Survey Satellite (TESS), which surveys the sky and collects light information on stars near and far. By looking at various kinds of light data from both telescopes, the researchers and their collaborators found that LP 40?365 is not only being hurled out of the galaxy, but based on the brightness patterns in the data, is also rotating on its way out.

“The star is basically being slingshotted from the explosion, and we’re [observing] its rotation on its way out,” says Putterman, who is second author on the paper.

“We dug a little deeper to figure out why that star [was repeatedly] getting brighter and fainter, and the simplest explanation is that we’re seeing something at [its] surface rotate in and out of view every nine hours,” suggesting its rotation rate, Hermes says. All stars rotate — even our sun slowly rotates on its axis every 27 days. But for a star fragment that’s survived a supernova, nine hours is considered relatively slow.

Supernovas occur when a white dwarf gets too massive to support itself, eventually triggering a cosmic detonation of energy. Finding the rotation rate of a star like LP 40?365 after a supernova can lend clues into the original two-star system it came from. It’s common in the universe for stars to come in close pairs, including white dwarfs, which are highly dense stars that form toward the end of a star’s life. If one white dwarf gives too much mass to the other, the star being dumped on can self-destruct, resulting in a supernova. Supernovas are commonplace in the galaxy and can happen in many different ways, according to the researchers, but they are usually very hard to see. This makes it hard to know which star did the imploding and which star dumped too much mass onto its star partner.

Based on LP 40?365’s relatively slow rotation rate, Hermes and Putterman feel more confident that it is shrapnel from the star that self-destructed after being fed too much mass by its partner, when they were once orbiting each other at high speed. Because the stars were orbiting each other so quickly and closely, the explosion slingshotted both stars, and now we only see LP 40-365.

“This [paper] adds one more layer of knowledge into what role these stars played when the supernova occurred,” and what can happen after the explosion, Putterman says. “By understanding what’s happening with this particular star, we can start to understand what’s happening with many other similar stars that came from a similar situation.”

“These are very weird stars,” Hermes says. Stars like LP 40-365 are not only some of the fastest stars known to astronomers, but also the most metal-rich stars ever detected. Stars like our sun are composed of helium and hydrogen, but a star that has survived a supernova is primarily composed of metal material, because “what we’re seeing are the by-products of violent nuclear reactions that happen when a star blows itself up,” Hermes says, making star shrapnel like this especially fascinating to study.

Story Source:

Materials provided by Boston University. Original written by Jessica Colarossi. Note: Content may be edited for style and length.

Cosmic galaxy assembly and the evolution of metals

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Cosmic galaxy assembly and the evolution of metals
A schematic of the evolution of the universe. Astronomers have measured the elemental abundances of galaxies that date from about 1.7 to 4.5 billion years after the big bang, and found that overall the processes producing the elements follow about the same scaling relationships as seen in the local universe. Credit: Argelander-Institut für Astronomie

Astronomers refer to all the elements heavier than helium as “metals,” even elements that are typically found in gaseous form. In the big bang only hydrogen and helium (and a trace of lithium) were created while the “metals” were all made subsequently in stellar processes. The abundance of metals in the interstellar medium (ISM) of galaxies—the metallicity of the galaxies—thus quantifies the collective stellar processes that govern galactic evolution. The metallicity of the gaseous phase of the ISM (excluding particulates) has been found to be closely related to the history of a galaxy’s star formation and can be determined using optical spectroscopic observations of atomic lines, especially bright ones from ionized oxygen and neon. Another pivotal process in setting the metallicity is gas flow both out of the galaxy, driven by supernovae or other processes, and into the galaxy from the intergalactic medium.

How the metallicity of has evolved over cosmic time has become one of the most interesting questions in cosmology because it traces how stars have influenced the elemental composition of the universe in the roughly thirteen billion years since they first appeared, roughly a hundred or more million years after the .

CfA astronomer Mojegan Azadi is a member of team performing the MOSDEF survey, a four year program using the Multi-Object Spectrometer For Infrared Exploration (MOSFIRE) on the Keck I telescope to obtain optical spectra of about 450 galaxies in epochs from 1.7 to 4.5 billion years after the big bang. The astronomers measured the metallicity of each galaxy in the sample and concluded that many of the relations involving metallicity in the local universe also apply at these earlier times. For example, the relationship between a galaxy’s metallicity and stellar mass is about the same, as is the correlation between metallicity and rate.

These important new results signal that the processes that govern the growth of the element abundances in galaxies, whether by gas flows or star formation, have held in about the same form for at least the past twelve billion years.


Less metal, more X-rays: New research unlocks key to high luminosity of black holes


More information:
Ryan L. Sanders et al, The MOSDEF Survey: The Evolution of the Mass–Metallicity Relation from z = 0 to z ∼ 3.3*, The Astrophysical Journal (2021). DOI: 10.3847/1538-4357/abf4c1

Citation:
Cosmic galaxy assembly and the evolution of metals (2021, August 2)
retrieved 3 August 2021
from https://phys.org/news/2021-08-cosmic-galaxy-evolution-metals.html

This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no
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A kinematic study of central compact objects and their host supernova remnants

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Vol. 651
7. Stellar structure and evolution

A kinematic study of central compact objects and their host supernova remnants

by M. G. F. Mayer and W. Becker 2021, A&A, 651, A40

Supernova remnants (SNRs) are the leftovers of supernovae, the results of powerful explosions. In the beginning, their gas expands at ~20,000 km/s. This velocity decreases with time, depending on the density of the surrounding ambient medium, which is snowplowed away. For relatively young SNRs, such as the ones considered in this study (~350 to 27,000 yr), one could expect expansion velocities of ~5,000 km/s.
Naively, one might imagine that SNRs do not change on timescales of a human lifetime. However, if observed at high angular resolution (as Chandra observations allow for) and over a sufficiently long temporal base (~10 yr), they can reveal their overall expansion, similar to that of an inflating balloon. A meticulous analysis of the X-ray data is needed to put this expansion on a firm statistical basis. This is done in the work by Meyer and Becker, which has revealed a hint of SNR expansion in two remnants. In addition, the authors were also able to measure or constrain the motion of the neutron star, the supernova leftover, excluding hyper-velocity objects..



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